1. Field of the Invention
This invention relates to hydraulic lifter devices and more particularly to a hydraulic lifter device installed in a valve train mechanism of an internal combustion engine.
2. Description of the Prior Art
In the prior internal combustion engine, a predetermined valve clearance is provided since there is a difference between thermal expansions of a cylinder head and a cylinder block and thermal expansions of a valve train mechanism. When the valve clearance is not properly maintained during the operation of the engine, noises will be occurred and the loss of the horse power will be occurred due to the blows of the crude gases. Therefore, the hydraulic lifter devices have been proposed to thereby maintain the valve clearance.
Such hydraulic lifter device includes a body having a reservoir chamber therein, a plunger disposed within the body so as to thereby define a pressure chamber, a check valve to allow a fluid flow only into the pressure chamber from the reservoir chamber and a leak clearance formed between the body and the plunger. The plunger is mechanically associated with a cam shaft and therefore the plunger is caused to be moved relative to the position of the body in response to the rotation of the cam shaft. More particularly, when the plunger is sunk relative to the position of the body, the fluid under pressure within the pressure chamber is flowed out through means of the leak clearance while when the plunger is extended relative to the position of the body, the check valve is caused to be opened to thereby allow the fluid flow into the pressure chamber from the reservoir chamber.
When the above hydraulic lifter device is installed in the inclined engine, namely, the mounting condition of the hydraulic lifter device is not perpendicular, however, the fluid within the reservoir chamber may be leaked through means of a fluid supplying passage which is formed in the body and leads to the reservoir chamber during the operation of the engine stops. Therefore, an air may be introduced within the pressure chamber from the reservoir chamber when the engine starts to operate. As a result, the plunger can not sink and extend by a predetermined distance and tapping noises will occur.